Cytokinin oxidase promoter from maize

Abstract

The present invention provides compositions and methods for regulating expression of nucleotide sequences in a plant. Compositions and methods include expression cassettes and transformed plants and provide for downregulation of cytokinin oxidase in a plant.

1. An expression cassette comprising a fragment of at least 21 consecutive nucleotides of SEQ ID NO: 4 operably linked to a promoter. 
     
     
       2. A plant, or its parts, stably transformed with the expression cassette of  claim 1 . 
     
     
       3. The plant of  claim 2 , wherein expression of said fragment results in downregulation of expression of cytokinin oxidase. 
     
     
       4. The plant of  claim 2 , wherein said plant is maize, barley, wheat, oat, rye, sorghum or rice. 
     
     
       5. The plant of  claim 2 , wherein said plant is soybean, alfalfa, safflower, tobacco, sunflower, cotton, or canola. 
     
     
       6. A method of downregulating expression of cytokinin oxidase in a plant, comprising transforming a plant cell with the expression cassette of  claim 1  and regenerating a stably transformed plant from said transformed cell. 
     
     
       7. The expression cassette of  claim 1  in which the fragment comprises at least 21 consecutive nucleotides of positions 1-1832 of SEQ ID NO: 4. 
     
     
       8. The method of  claim 6 , wherein (a) expression of native cytokinin oxidase is downregulated and (b) expression of transgenic cytokinin oxidase is not downregulated.